Robust minimun variance beamforming applied to ultrasound imaging in the presence of phase aberration

Minimum variance (MV) adaptive beamforming has been applied in medical ultrasound imaging to improve lateral resolution, but standard MV method is quite sensitive to the perturbation of the received signal. Due to the inhomogeneity of human tissues, sound speed varies and there exists a certain amount of time-delay error for each channel which is referred to as phase aberration. A robust minimum variance adaptive beamforming method was proposed in order to avoid significant degradation under more practical circumstances. The sample covariance matrix was reconstructed with a forward-backward method. And the steering vector was estimated via maximizing the output beamformer power, which was turned into a quadratic convex optimization problem with proper constraints. The simulations with Field II showed that the proposed method was robust in the presence of phase aberration and could maintain its performance for improving imaging quality.